From Latin *nox, noctis* ("night"), which shares its root with Ancient Greek *nýx* and English *nocturnal*. The Proto-Indo-European root *\*nókʷts* is found across dozens of European languages, reflecting how fundamental the night-day cycle was to early human life.

Spanish night culture is famously late: dinner (*la cena*) rarely starts before 9 p.m., and phrases like *buenas noches* serve both as "good evening" and "good night." The expression *de la noche a la mañana* ("from night to morning") means something happened overnight or very suddenly — a useful idiom to know.